Method and device for stacking sheet material

ABSTRACT

A spiral slot stacker has a two-part stripper  2  for stripping out sheet material from a stacker wheel  1 . The two parts  2   a   , 2   b  of the stripper are movable. A first part  2   a  of the stripper is moved out of the stacker wheel together with the last bank note  100  to be stacked in such a way, that only the last bank note is stripped out and the next bank note  101  remains in the stacker wheel. The second part  2   b  of the stripper at this stage rotates along with the stacker wheel and will not be locked in the strip-out position until the spiral slot stacker is prepared for stacking a next bank-note stack. The bank notes, in the meanwhile supplied to the stacker wheel, are stripped out from the stacker wheel by the second part  2   b  of the stripper, while the first part  2   a  of the stripper is moved back to the strip-out position. By this method a collision of the first part of the stripper with the bank notes located in the stacker wheel is prevented.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Phase of International Application SerialNo. PCT/EP03/08434, filed Jul. 30, 2003.

FIELD OF THE INVENTION

The invention relates to a method for stacking sheet material as well asa spiral slot stacker, in particular for the use in a bank noteprocessing apparatus.

DESCRIPTION OF THE BACKGROUND ART

In conventional bank note processing machines the bank notes generallyare singled in a stack and led past a sensor device by means of atransport path. The individual bank notes are checked by sensors of thesensor device and dependent on the checking result are supplied tocertain final destinations or stacker units.

For checking the bank notes several sensors can be provided, which judgethe bank notes according to different criteria. Accordingly, severalstacker units are available, which stack the bank notes of the differentcategories into units of an adjustable piece number. If for example banknotes of a certain category are to be stacked in units of a piece numberof 100 bank notes, it is necessary to perform a separation in thecontinuous flow of bank notes between the one hundredth bank note andthe following bank note meant for the same stacker after the onehundredth bank note has arrived at the stacker.

In connection with this, from DE-PS 34 12 725 it is known to use twostackers for bank notes of the same category. If 100 bank notes areplaced in the respectively active stacker, the following bank notes willbe supplied to the second identically constructed stacker via a diverterin the transportation system. In this known solution it is necessary toprovide two stackers of the same construction and the respectiverequired space.

From EP-OS 0 119 814 is known a solution, which requires only onestacker per bank note category. For this purpose on the stacker isprovided a separation element. At first this separation element is in anidle position until, analogously to the above-mentioned example, 100bank notes have been stacked. After that the separation element isinserted into the flow of bank notes between the one hundredth bank noteand the bank note following thereupon in such a way, that the followingbank notes are temporarily stored on the separation element. Meanwhile,the stacked unit of bank notes can be emptied. After the emptying thetemporarily stored bank notes are stored in the stacker. The separationelement returns to its idle position.

This solution has the disadvantage, that with higher transportationspeeds a relatively high actuating power for accelerating the separationelement has to be summoned, which can only be achieved with acorrespondingly high effort. With such a high transportation speed areliable operation of the stacker cannot be guaranteed.

In DE 44 37 722 A1 it is proposed to interrupt the delivery of banknotes to the transportation system instead, when the sensor devicedetects that the predetermined piece number of a category has beenreached. The bank notes of the same category already singled at thispoint of time are temporarily stored in the sorter, until the readystacked bank-note stack has been removed. The temporary storage can beperformed in the stacker itself or in a buffer path integrated in thetransport path. This solution has the general disadvantage that themachine due to the interruption works in a discontinuous fashion.

In the solution in which the already singled bank notes are stored inthe stacker itself, the stacker has the form of a spiral slot stacker,as for example described in DE-OS 32 32 348. However, the stripper forstripping out the bank notes accommodated in the slots of the stackerwheel is designed to be movable in such a way that it can be moved outof the stacker wheel or into the stacker wheel. The components interactwith each other in such a way that the movable stripper when moving outof the stacker wheel strips out the one hundredth bank note onto thestack deposit, and that the bank notes located in the next slots of thestacker remain therein. In the meantime, the stacker wheel furtherrotates and accommodates the bank notes which had already been singledat the point of interruption. As soon as the stack deposit is emptiedand prepared for stacking a next bank-note stack, the stripper again ismoved into the stacker wheel. Then the stacking operation is continuedin the usual fashion.

The disadvantage in this solution is that the stacker wheel has to bestopped, so as to enable the stripper to move again into the stackerwheel. Because with a rotating stacker wheel there exists the dangerthat the stripper collides with the bank notes located in the slots,before it has reached its strip-out position. However, this means thatthe transportation system does not only have to be interrupted as soonas the predetermined piece number of a category has been reached, butpotentially once again when the stripper is moved back into the stackerwheel.

SUMMARY OF THE INVENTION

It is the problem of the present invention to propose a method and anapparatus for stacking sheet material, in which the delivery of banknotes to the transportation system not necessarily has to be interruptedwhen the predetermined piece number of a category has been reached, orthat such an interruption time at least is kept short.

This inventive solution starts out from a spiral slot stacker accordingto DE 44 37 722 A1, in which the sheet material is temporarily stored inthe stacker wheel. I.e., for example the one hundredth bank note isstripped out from the stacker wheel by means of a movable stripper,while the bank notes in the next slots remain in the stacker wheel. Inso far herewith reference is made to DE 44 37 722 A1 including theconstructive proposals for solution described therein.

As to prevent the stripper from colliding with the bank notes located inthe stacker wheel when moving into the stacker wheel or having to stopthe stacker wheel as to avoid such a collision, the stripper is formedat least in a two-part fashion, only a first part being moved out of thestacker wheel in the described fashion. At the time the first part ofthe stripper is moved out of the stacker wheel, the second part of thestripper is released from its strip-out position. The second part of thestripper is movable, too. It is, however, not moved out of the stackerwheel but rotates along with the stacker wheel after having beenreleased from the strip-out position. Meanwhile, further bank notes aresupplied to the stacker wheel, in such a way that the delivery of banknotes to the transportation system of the bank note processing machinehas not to be interrupted.

There are two alternative embodiments:

According to the first embodiment, the second part of the stripperrotates along with the stacker wheel until the stack deposit is preparedto receive a next bank-note stack and the second part of the stripperagain has reached its strip-off position. Then it is again locked in thestrip-off position, the stacker wheel still further rotating. By thismeans it is achieved that the bank notes located in the stacker wheelare stripped out of the stacker wheel and stacked on the stack depositby the second part of the stripper beginning with the moment of locking.Now the first part of the stripper can be moved back to its strip-outposition on the same path on which it has been moved out of the stackerwheel. A collision with the bank notes located in the stacker wheel isexcluded, since these are stripped out of the stacker wheel by thesecond part of the stripper.

However, in this solution, too, in rare cases it can occur, that a banknote provided for the spiral slot stacker cannot be introduced into aslot of the stacker wheel, this is the case when the supply is blockedby the moved-along second part of the stripper. Only few slots of thestacker wheel are affected by this blocking. The problem can be easilyavoided by driving the stacker wheel in an accelerated fashion in thisphase, so as to the respective slots are rapidly turned past the banknote supply position. If this is not sufficient as to avoid a collisionof a bank note to be supplied to the stacker wheel with therotating-along part of the stripper, it is expedient to integrate abuffer path into the transport path, as it is proposed in DE 44 37 722A1 as a second alternative. In so far, too, reference is made to DE 4437 722 A1.

According to the second embodiment the second part of the stripperrotating along with the stacker wheel is moved back to its strip-outposition against the rotating direction of the stacker wheel and locked.This has the advantage that it is not moved past the bank note supplyplace and the supply of further bank notes to the stacker wheel thus isnot blocked. However, this second embodiment is only practicable, whenthe second part of the stripper has not moved too far away from thestack deposit, since though the bank notes are stripped out of the slotswhen the second stripper part is moved back, they would not be stackedon the stack deposit in a reliable fashion. With this embodiment,therefore, it is important that the stack deposit is prepared as rapidlyas possible for receiving the next bank-note stack to be stacked. Thiscan be achieved, for example, by pushing aside the ready stackedbank-note stack or, according to a preferred embodiment, by moving anauxiliary stack deposit over the stack deposit with the ready stackedbank-note stack. As soon as the auxiliary stack deposit has taken itsposition, the moved-along second part of the stripper can be moved backto its strip-out position, the bank notes located in the stacker wheelslots in between being stripped out onto the auxiliary stack deposit.Then, again the first part of the stripper, which was moved out of thestacker wheel, is moved back into the stacker wheel. Then the stackingoperation is continued in the usual fashion.

The auxiliary stack deposit and the stack deposit preferably aredesigned in the manner of a rake in such a way that they can be broughtto the same level when the ready stacked bank-note stack has beenremoved from the stack deposit.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is described by way of example withreference to the accompanying figures.

FIGS. 1 a to 1 d show a first embodiment of the invention,

FIGS. 2 a and 2 b show a second embodiment of the invention and

FIGS. 3 a and 3 b show a third embodiment of the invention.

FIG. 4 shows a partial exploded view of a stacker wheel with a stripperpart and a drive therefore.

FIG. 5 corresponds to the view in FIG. 4, without the stacker wheel.

FIG. 6 corresponds to the view in FIG. 5, with the stripper part shownin two extreme positions.

FIGS. 1 a and 1 d show a spiral slot stacker of a bank note processingmachine at different points of operation. The bank note processingmachine not shown in detail herein is constructed in a way as describedin DE 44 37 722 A1, including transport systems, diverters, sensors andthe like. Of course, the spiral slot stacker described in the followingis also suitable for stacking sheet material in other apparatuses.

DETAILED DESCRIPTION OF THE INVENTION

The spiral slot stacker has a stacker wheel 1 with slots spirallydisposed one behind the other around a rotational axis. The rotatingdirection of the stacker wheel is indicated by an arrow. To the stackerwheel 1 bank notes 98 to 104 are supplied successively. FIG. 1 a showsthe spiral slot stacker 1 just at the time the bank note 104 issupplied.

A stripper 2 in a usual fashion engages with the spiral slot stacker.For this purpose the slots accommodating the bank notes are formed bystacker wheel fingers 3 disposed side by side and spaced apart from eachother, between which the stripper 2 with stripping fingers suitablyadapted and disposed side by side moves into engagement. In FIG. 1 a thespiral slot stacker is schematically shown in section, in such a waythat merely one stripping finger and one stacker wheel finger plane isshown.

Due to the rotation of the stacker wheel 1 and the rotation of thestripper 2 engaging with the stacker wheel 1 the bank notes located inthe stacker wheel 1 are transported towards the stripper 2, whichsuccessively strips out these bank notes from the slots of the stackerwheel 1 onto a stack deposit 4 located therebelow. By this means on thestack deposit 4 is formed a bank-note stack 5, to which at the time asshown in FIG. 1 a the 98th bank note 98 is supplied.

When the number of bank notes required for the bank-note stack 5, forexample 100 bank notes, is reached, the stacking operation isinterrupted, so that the bank-note stack 5 can be taken out from thestack deposit 4, before the stacking of the next bank-note stack begins.For this purpose the stripper 2, as described in DE 44 37 722 A1, ismoved out of the stacker wheel 1 in such a specific way that the onehundredth bank note 100 is the last to be stripped out from the stackerwheel 1 onto the bank-note stack 5, as indicated in FIG. 1 b.

In contrast to DE 44 37 722 A1, however, only a part 2 a of the stripper2 is moved out of the stacker wheel 1 roughly in the direction of theshown arrow, while a second part 2 b of the stripper is moved along withthe rotating stacker wheel 1. For this purpose each stripping finger ofthe stripper 2 is divided into two parts 2 a, 2 b. Alternatively, everysecond stripping finger can be designed as a moved-along strippingfinger 2 b and the remaining stripping fingers as stripping fingers 2 aadapted to be moved out.

The movement of the stripper part 2 a by suitable measures is correlatedwith the rotation of the stacker wheel 1 in such a way that the desiredpurpose is achieved, namely to strip out a specific bank note as a lastbank note and to leave the next bank note in the stacker wheel. For thispurpose the stripper part 2 a can have a separate, electronicallycontrolled drive or be designed to be mechanically coupled to a contourdisk, as described in DE 44 37 722 A1.

A not shown locking of the second part 2 b of the stripper 2 for fixingit in the strip-out position as shown in FIG. Ia is released at the timethe first part 2 a of the stripper 2 is moved out of the stacker wheelI. As to achieve the result that the second part 2 b of the stripper 2rotates along with the stacker wheel 1, there can be provided a separatedrive. But the effort connected with a separate drive can be avoided,when the second part 2 b of the stripper in the moment of being releasedfrom the locking is coupled to the stacker wheel 1. For this purpose thestripper is connected to the driving shaft of the stacker wheel 1 via anot shown coupling and locked in its strip-out position by means of arelease mechanism 7 or is released via the release mechanism 7 afterhaving stripped out the one hundredth bank note, so that itsynchronously rotates with the stacker wheel 1. Instead of a mechanicalrelease mechanism the coupling can have the design of a magneticcoupling adapted to be electrically actuated.

FIG. 1 c shows the stacker wheel 1 with the rotating-along part 2 b ofthe stripper 2 and the first part 2 a of the stripper 2, which iscompletely moved out of the stacker wheel 1, after the one hundredthbank note 100 was stripped out onto the bank-note stack 5. Meanwhile,the 106th bank note 106 is transported to the stacker wheel 1.

Now the bank-note stack 5 is removed from the stack deposit 4, so as toprepare the stack deposit for receiving the next bank-note stack. Afterhaving prepared the stack deposit 4 for receiving a next bank-notestack, the stacker wheel 1 further rotates until the second part 2 b ofthe stripper 2 again has reached the strip-out position according toFIG. 1 a. This is shown in FIG. 1 d. Since in the meanwhile further banknotes 107 to 112 have been supplied to the stacker wheel 1, inindividual slots of the stacker wheel 1 are located two or, optionally,more bank notes, when the second part 2 b of the stripper 2 againreaches its strip-out position. The second part 2 b of the stripper 2then again is locked in the strip-out position, in such a way that thebank notes located in the slots of the stacker wheel are stripped outonto the stack deposit 4 by the second part 2 b of the stripper 2 in theusual fashion. Then the first part 2 a of the stripper 2 can be movedback to the strip-out position, too. A collision with the bank noteslocated in the stacker wheel is not possible here, since in themeanwhile these bank notes are stripped out by the second part 2 b ofthe stripper 2. For this reason, in particular the stacker wheel 1 needsnot to be stopped, when the first part 2 a of the stripper 2 is movedback to the strip-out position.

In FIGS. 2 a and 2 b a second embodiment of the spiral slot stacker isshown, which in principle works in the same way as the embodimentpreviously described with respect to the FIGS. 1 a to 1 d. FIG. 2 ashows the stacker wheel 1 at the same time of operation as in FIG. 1 c.The procedure of the method in so far is identical. In contrast to theembodiment according to FIGS. 1 a to 1 d, after completing the bank-notestack 5 by stripping out the one hundredth bank note 100, an auxiliarystack deposit 6 is introduced between the stacker wheel 1 and thebank-note stack 5, in such a way that the spiral slot stacker isconsiderably faster prepared for stacking a next sheet material stack.By this means the moved-along second part 2 b of the stripper again canbe locked in the strip-out position as early as after one revolution ofthe stacker wheel 1.

Preferably, the stack deposit 4 and the auxiliary stack deposit 6 aredesigned in a comblike fashion. At first the stack deposit 4 togetherwith the bank-note stack 5 is lowered, so that the auxiliary stackdeposit 6 can be positioned thereabove. After the bank-note stack 5 hasbeen removed from the stack deposit 4, the stack deposit is lifted tothe level of the auxiliary stack deposit 6 with the bank notes 101, 109,102, 110 etc. temporarily stored thereon in such a way that the teeth ofthe two deposits 4 and 6 engage in a comblike fashion and constitute ajoint deposit level. As to prevent a collision of the auxiliary stackdeposit 6 with the first part 2 a of the stripper 2 moved out of thestacker wheel 1, the introduction of the auxiliary stack deposit 6 isperformed, for example, in a direction parallel to the axis of rotationof the stacker wheel.

As recognizable from FIGS. 1 a to 1 d and 2 a, 2 b, the supply offurther bank notes to individual slots of the stacker wheel 1 istemporarily blocked by the second part 2 b of the stripper 2 which isrotating along with the stacker wheel 1. If these slots cannot be movedpast the bank note supply location, before the stacker wheel 1 issupplied with a next bank note, this next bank note has to betemporarily stored, for example in a buffer path integrated in thetransport path. The technical effort required for such a buffer path canbe avoided, when the spiral slot stacker is designed as shown in FIGS. 3a, 3 b. Here again the auxiliary stack deposit 6 is employed, whichenables the beginning of stacking a next bank-note stack even before thebank-note stack 5 has been removed from the stack deposit 4.

FIG. 3 a shows the spiral slot stacker in the same position as in FIG. 2a. In contrast to the embodiments described until now, the second part 2b of the stripper 2, however, is moved along with the stacker wheel 1only as long as the one hundredth bank note 100 has been stripped outonto the stack deposit 4. Then the stack deposit 4 is lowered, theauxiliary stack deposit 6 is positioned over the lowered stack deposit4, and the second part 2 b of the stripper 2 is moved back to thestrip-out position in an opposite direction as the rotating direction ofthe stacker wheel 1. FIG. 3 b shows the stacker wheel 1 with the secondpart 2 b of the stripper 2 moved back to the strip-out position and theintroduced temporary stack deposit 6. The stripping out of the firstbank note 101 for the next bank-note stack begins with the moving backof the second part 2 b of the stripper 2 to the strip-out position andis completed roughly at the time when the auxiliary stack deposit 6 hasreached its position for stacking the next bank-note stack.

As is shown in FIGS. 4, 5 and 6, the stripper part 2 b and the stackerwheel 1 are arranged on a common axis. The stripper part 2 b is mountedby means of a dragging clutch so that it will move along with thestacker wheel 1 whenever no other forces or torques are acting on thestripper part 2 b. Movement in the direction of rotation of the stackerwheel 1 (see arrow in FIG. 4) is limited by a stopper 100, thus definingthe upper position in FIGS. 4, 5 and 6.

A stepper motor 102 is used to move the stripper part 2 b in theopposite direction. The shaft of the stepper motor 102 is arrangedcoaxially with respect to the axis of the stacker wheel 1, and isconnected to a disc 104 bearing a radially extending engaging piece 106.An engaging rod 108, attached to the stripper part 2 b, is arranged suchthat it is moved by the engaging piece 106. Thus, by activating thestepper motor 102, the stripper part 2 b can be moved against thedirection of rotation of the stacker wheel 1 via the engaging piece 106and the engaging rod 108. Control of the stepper motor 102 can besimplified by limiting the movement of the engaging rod 108 by means ofan additional stopper 110. In this manner, the engaging rod 108 and thestripper part 2 b can be locked in the lower position, as shown in FIG.6. When the stepper motor 102 is powered off, the stacker wheel 1 movesthe stripper part 2 b back by means of the dragging clutch.Alternatively, the stripper part 2 b may be coupled to the shaft of thestepper motor 102, either directly or via a transmission, so that thestripper part 2 b is moved and locked by means of the stepper motor 102alone.

The above-described dragging clutch may be replaced with an electricallyactuatable magnetic clutch, in which the shafts of the clutch arecoupled with the stacking wheel 1 and the stripper part 2 b. In order tomove the stripper part 2 b along with the stacking wheel 1, the magneticclutch is closed, otherwise, the magnetic clutch is open. Alternatively,the stopper 110 may be replaced with an electrically actuatable latch.In this case, a simple motor is used instead of the stepper motor 102,and the latch may be arranged such that it permits the engaging rod 108to pass, in its locked state, when the engaging rod 108 rotates againstthe direction of rotation of the stacker wheel, and blocks the engagingrod 108 when it rotates in the direction of rotation of the stackerwheel. Thus, the motor turns the stripper part 2 b of the engaging rod108 to such an extent that the engaging rod 108 passes the latch. Themotor can then be powered off so that the stripper part 2 b is locked bymeans of the latch and the force of the dragging clutch. In order tomove the stripper part 2 b with the stacker wheel 1, it is sufficient toelectrically release the latch. Of course, there are other options thatmay achieve the desired function, as known in the art.

Now the first part 2 a of the stripper 2, without a danger of collisionwith the bank notes located in the stacker wheel 1, can be moved intothe stacker wheel 1. After the bank-note stack 5 being removed from thedeposit plate 4, the stack deposit 4 is lifted in the fashion describedhereinbefore to the level of the auxiliary stack deposit 6, and the saidauxiliary stack deposit can be moved out of its comblike engagement withthe stack deposit 4.

1. Spiral slot stacker for stacking sheet material, comprising: astacker wheel with slots spirally disposed one behind the other around arotational axis for receiving the sheet material, a stripper including afirst movable part and a second movable part, the first and secondmovable parts being movable into, and out of, respective first andsecond strip-out positions in which the first and second movable partsstrip out the sheet material from the slots of the stacker wheel, and astack deposit for stacking the sheet material stripped off the slots,wherein the first movable part of the stripper moves out of the firststrip-out position, while the stacker wheel is rotating, in such a waythat the sheet material is stripped out from one of the slots of thestacker wheel and the sheet material of a next slot remains in thestacker wheel, and wherein the second movable part of the stripper islockable in the second strip-out position and, when released, moves outof the second strip-out position and rotates along with the rotatingstacker wheel.
 2. Spiral slot stacker according to claim 1,characterized by an auxiliary stack deposit, which is adapted to bemoved between the stack deposit and the stacker wheel.
 3. Spiral slotstacker according to claim 2, characterized in that the auxiliary stackdeposit and the stack deposit are adapted to be brought to the samelevel and to engage in a comblike fashion.
 4. Spiral slot stackeraccording to claim 2, characterized in that the auxiliary stack depositand the stack deposit are adapted to be brought to the same level and toengage in a comblike fashion.
 5. Bank note processing apparatuscomprising one or several spiral slot stackers according to claim
 4. 6.Bank note processing apparatus comprising one or several spiral slotstackers according to claim
 2. 7. Bank note processing apparatuscomprising one or several spiral slot stackers according to claim
 3. 8.Spiral slot stacker according to claim 1, characterized in that thesecond part of the stripper is adapted to be moved back to the strip-outposition in an opposite direction to the rotating direction of thestacker wheel.
 9. Bank note processing apparatus comprising one orseveral spiral slot stackers according to claim
 8. 10. Bank noteprocessing apparatus comprising one or several spiral slot stackersaccording to claim
 1. 11. Method for stacking sheet material by means ofa spiral slot stacker, which comprises a stacker wheel, which has slotsspirally disposed one behind the other around a rotational axis forreceiving the sheet material, comprising the following steps: supplyingthe sheet material into the slots of the stacker wheel, stripping outthe sheet material from the slots of the stacker wheel onto a stackdeposit by means of a stripper being in a strip-out position for forminga sheet material stack, when a predetermined number of sheets isreached, moving a first movable part (2 a) of the stripper out of thestrip-out position, while the stacker wheel rotates, in such a way thatthe last sheet of the predetermined number of sheets is stripped outfrom the stacker wheel and the sheet material of a next slot remains inthe stacker wheel, preparing the spiral slot stacker for stacking a nextsheet material stack, moving back the first part of the stripper to thestrip-out position, releasing a second movable part of the stripper fromthe strip-out position and moving along with the rotating stacker wheel,when the first part of the stripper is moved out of the strip-outposition, further supplying sheets into the slots of the stacker wheel,while the second part of the stripper rotates along with the stackerwheel, locking the second moved-along part of the stripper in thestrip-out position, when the spiral slot stacker is prepared forstacking the next sheet material stack, and stripping out the sheetmaterial located in the slots by means of the locked second part of thestripper, while the first part of the stripper is moved back to thestrip-out position.
 12. Method according to claim 11, the step ofpreparing the spiral slot stacker for stacking a next sheet materialstack comprising the following steps: introducing an auxiliary stackdeposit over the stack deposit for temporarily stacking the next sheetmaterial stack thereon, removing the sheet material stack from the stackdeposit, and bringing the auxiliary stack deposit, with the temporarilystacked sheet material stack, and the stack deposit to the same level,after the sheet material stack was removed from the stack deposit. 13.Method according to claim 12, the second part of the stripper beingmoved back in an opposite direction as the rotating direction of thestacker wheel, as to lock the said second part of the stripper in thestrip-out position.
 14. Method according to claim 11, the second part ofthe stripper being moved back in an opposite direction as the rotatingdirection of the stacker wheel, as to lock the said second part of thestripper in the strip-out position.